CD110

CD110, also known as MPL, is a cell surface receptor for thrombopoietin (TPO) and a member of the type I cytokine receptor family. It is designated in the CD nomenclature as CD110. The MPL-encoded protein is expressed on hematopoietic stem cells and megakaryocyte progenitors, as well as platelets to varying degrees.

Binding of TPO to MPL induces receptor dimerization and activates associated JAK2 tyrosine kinase, triggering downstream signaling through the JAK-STAT, MAPK, and PI3K-AKT pathways. This signaling promotes megakaryocyte development and platelet production and helps maintain hematopoietic stem cell quiescence and self-renewal.

Mutations and alterations of MPL can contribute to disease. Inherited MPL mutations can cause congenital amegakaryocytic thrombocytopenia, a rare platelet disorder. Acquired MPL alterations, including mutations such as W515L and W515K, as well as altered expression, are found in myeloproliferative neoplasms (MPNs) and can cooperate with other driver mutations such as JAK2 V617F.

Therapies directly targeting MPL include thrombopoietin receptor agonists, such as romiplostim and eltrombopag, used to treat chronic immune thrombocytopenia and other thrombocytopenias by stimulating MPL to boost platelet production.